 Hello, welcome back on my YouTube channel. In today's video, we're going to explore a tool to very quickly delineate streams and catchments from a digital elevation model. We're going to use a tool from Hatari Labs. Hatari Labs, run by Sol Montoya, offers great courses on groundwater using open source software. They've developed Hatari Utils that run online. And as they claim here, the least painful tool for advanced hydrological analysis. So let's see if that's true. Click the sign in login button. And there, sign in at Hatari Labs' apps account. Click continue. And there, if you're new, click register. Fill in the registration form. And click register. Then you verify your account and click sign in to use the apps. Currently, you can create only one project. Click add project and give the name of the model that you're working on. And I'm going to call it Roar. And the model description Roar Catchment. These are mandatory fields. Then click edit to work on your project. Here you see that you can choose from different apps from Hatari Labs. And we're going to use the first one, watershed delimitation. Now click on watershed delimitation to start the app. The first thing you need to do is to upload a DEM file. This can be in any projection, but it accepts around 10 megabyte GeoTIF files. And after uploading, it pre-processes the files. And then you can see the result here with the flow direction and the flow accumulation. That's exactly what you can also find under the pre-processed tab. Now let's go to the delineation tab. There it will load the map with the stream network delineated already for you. And you can use this map to specify your port point and to only accept it when you click on the line and you can see how the hand changes. Then if you click, it will add the coordinates in latitude and longitude, independent of the input data that you've used. And there you see the result, the delineated catchment, the stream network, and the main river. Then go to basin stats. There you find the main statistics of this catchment, including some metrics. If you go to river profile, you find the elevation over the distance along the river. And under time of concentration, you can find the time of concentration with different methods, for example, here pitch. Now click the download tab. This will download a zip file with all the generated data. Let's check this data after extracting the zip file in QGIS. Under input, you find your input DEM. And under process, you can find the result shape files. Let's drag them to the map canvas. Here we have our catchment. And note that the results are in the same projection as your input DEM. So in this case, it's EPSG4326. But I want to visualize it in UTM zone 32 because then it looks better. So I changed on the flyer reproduction. And I'm going to add here the other layers. The main river doesn't show up because the projection is not detected, river basin and river network. So the layers that have a projection, they show up nicely. Let's style them to a simple blue line for the river network. If I go to the attribute table, you see that it only has a FID. And it does not have strata orders or anything else. It's just a stream network. Then the river basin, choose there the FID. And I can use random colors. It will show a random color for each tributary, which has its own sub-basin. But it doesn't delineate each sub-basin there. And then for the main river, there's this question mark, which means that the projection is not defined. And I need to use there the projection of the original input, which is EPSG4326. And there I see the main river. And also that attribute table has only ID and distance. And let's use a simple line for the outline of the catchment boundary. So these are the results. Now I'm going to do another one. Remember, you can only make one project. So I delete the one that I have and I create a new one. I'm going to use a gold creek in Australia. And I'm going to show how it works when your DEM is already projected. Click Edit. Click Watershed Delimitation to go to the app. Choose the DEM and click Upload. There it generates the result of the preprocessing. So there's the flow direction and flow accumulation. You see here that it says Latitude Longitude. But in fact, it also shows the UTM coordinates. And the flow direction legend is based on the ArcGIS encoded. So 1, 2, 4, et cetera. Now go to the delineation tab. There you see the river network. And I'm going to click there on the port point. It takes the coordinates there. That's in Latitude Longitude, although the input is in UTM. And I click Define Watershed. And there it nicely delineates the catchment and shows the mainstream and the river network. I'm going to download it and then visualize it in QGIS. There's our input file in UTM coordinates. And there I'm going to add each layer again. Catchment, main river, river basin, and the river network. And now the main river was in the same projection, but it's not known. But so it shows up at the right spot because we didn't change the on-the-fly projection like previously. So this works nicely. I think a very nice and quick way to delineate streams and catchments if you don't want to go through all the steps in QGIS for doing that. The disadvantage is that there's a limitation of the size that you can upload for the DEM. And you have no control on the algorithms that are used. So some study areas need specific approaches, specific algorithms to be used. And therefore I think it's also important to know the processing steps in GIS to derive streams and catchments. I can recommend to follow Hatari Labs on social media and find out about their tutorials and their super nice courses on groundwater and open source GIS. And I hope you like this video and subscribe to my YouTube channel. 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